1. Field of the Invention
The present invention relates generally to wiper assemblies for vehicles and, more specifically, to a heated wiper assembly for a vehicle.
2. Description of the Related Art
Conventional wiper assemblies for vehicles known in the related art include some type of wiper assembly mounted to a wiper arm which, in turn, is mounted adjacent a surface to be wiped such as a windshield of the vehicle and pivotally driven to impart reciprocal motion to the wiper assembly across the windshield. The wiper assembly typically includes a rubber wiping element that contacts the windshield across the surface to be wiped. The wiper assembly often incorporates one or more metal strips that act to reinforce the wiping element and facilitate wiping contact by the wiping element across what is typically a curved glass surface. In this context, the wiper arm delivers a downward force to the wiper assembly that is distributed thereacross pressing the wiper assembly into contact with the windshield. The wiper assembly may also include an airfoil and a pair of end caps located at the distal ends of the wiper assembly.
Currently, for winter driving conditions, snow and ice typically accumulate on the wiper assembly, which is undesired. In freezing conditions where water is present in liquid form either from the environment such as sleet, rain or road slush, or introduced by melting ice and snow on the windshield, the wiping element has a tendency to ice up. When the wiping element is iced up, in particular around a hinge and wipe lip of the wiping element, the effectiveness to clear the glass surface is severely impaired. In some cases, the wiping element can freeze to the glass surface and cause damage to the wiper system when subjected to loading from the wiper arm when the wiper system is turned on or activated. Severe impairment or damage to the wiper assembly could result in a loss of clear vision by the driver and potentially dangerous operating conditions.
Current state of the art of heated wiper blades utilize the following methods for applying heat to the blades: 1) heater wire inside the rubber wiping element; 2) heated film paper laid on top of the metal strips; and 3) heated wires adhered directly to the top of the metal strips. In the case of heater wire inside the rubber wiping element, this posses an issue with wipe quality because the rubber wiping element stiffness is affected due to the internal wire adding ridged or near ridged support inside the cross-section of the wiping element. This can also pose issues with non-reversal at either end of blade travel or non-conformance to curvature variation in windshield profile. In the case of heated film paper laid on top of the metal strips, this can pose issues with heat transfer due to misplacement of heated carrier. It also adds additional labor and can increase cost associated with adding such parts and does not necessarily allow for proper heat transfer to the very end of the rubber wiping element. In the case of heated wires adhered directly to the top of the metal strips, this can be very costly to process. It also does not allow for a connection around the end of the rubber wiping element and thus may allow for an ice build up around the tip of the rubber wiping element. Therefore, there is a need in the art to provide for an effective heating of the wiping element to preclude snow and ice buildup on the wiper assembly during winter driving conditions.